Insulin-like growth factor binding protein concentration and post-translational modification in embryological fluid

Area of Science:

• Reproductive biology
• Endocrinology
• Maternal-fetal medicine

Background:

• Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are crucial for fetal development.
• The distinct roles and modifications of IGFBPs in early pregnancy fluids remain incompletely understood.

Purpose of the Study:

• To compare concentrations and modifications of IGFBPs and IGFs in maternal serum, coelomic fluid, and amniotic fluid during early gestation (6-12 weeks).
• To investigate proteolytic activity and IGFBP-1 phosphorylation patterns in these fluids.

Main Methods:

• Analysis of matched maternal serum, coelomic fluid, and amniotic fluid samples from 21 pregnancies.
• Quantification of IGFBP-1 to -3, IGF-I, and IGF-II using immunoassays.
• Assessment of IGFBP-1 phosphorylation status and proteolytic activity.

Main Results:

• IGF-I was highest in maternal serum; IGF-II was highest in maternal serum but detectable and age-correlated in coelomic fluid.
• IGFBP-1 concentrations were higher in coelomic fluid (non-phosphorylated) than maternal serum (phosphorylated) or amniotic fluid.
• Coelomic fluid exhibited lower protease activity and higher IGFBP-2 and IGFBP-3 concentrations compared to maternal serum.

Conclusions:

• Distinct IGFBP profiles and post-translational modifications exist between maternal serum and early embryonic fluids (coelomic and amniotic).
• The composition of coelomic fluid, with high IGF-II and non-phosphorylated IGFBP-1, may promote mitogenic activity in the early gestational sac.
• These findings suggest differential regulatory pathways governing IGF system components in early pregnancy.